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. 2018 Feb 22;15(2):379. doi: 10.3390/ijerph15020379

Table A25.

Summary of findings table for the association between road traffic noise exposure and the incidence of ischaemic heart disease: ecological studies.

Question Does Exposure to Road Traffic Noise Increase the Risk of IHD
People Adult population (men and women)
Setting Residential setting: people living in Kaunas (Lithuania)
Outcome The incidence of IHD
Summary of findings RR per 10 dB increase in road traffic noise level (LDEN) 1.12 (95% CI: 0.85–1.48) per 10 dB
Number of participants (# studies) 262,830 (1)
Number of cases 418
Rating Adjustment to rating
Quality assessment Starting rating 1 ecological study 1 (very low) #
Factors decreasing confidence Risk of bias Serious a Downgrading
Inconsistency Na b No downgrading
Indirectness None c No downgrading
Imprecision None d No downgrading
Publication bias NA e Downgrading
Factors increasing confidence Strength of association NA f No upgrading
Exposure-response gradient Evidence of non-significant exposure-response gradient f No upgrading
Possible confounding No conclusions can be drawn g No upgrading
Overall judgement of quality of evidence 0 (very low) h

# Since only one ecological study was available, we started with a grading of “very low” (1); a Ecological studies worked with a purposeful sample; so randomization and response rate is not an issue. The study was not able to adjust for important confounders at individual level, and was unable to apply individual exposure estimates; b Only one study was evaluated, so inconsistency was not an issue; c The study assessed population, exposure and outcome of interest; d Although the 95% CI contained values above 1.25, we considered the results to be precise: the number of participants, as well as the number of cases were much larger than 200; e Due to the low number of available effect estimates, it was not possible to test for publication bias or small study bias. However, when combining this study with the other case-control and cohort studies that investigated the association between road traffic noise and the incidence of IHD, the number of estimates became large enough to test for publication bias. The funnel plot (Figure 5.6 of the complete review) was somewhat a-symmetric, but the Egger test provided only weak evidence for small-study effects; f There was evidence of a non-significant exposure-response gradient: We found a non-significant effect size of 1.12 per 10 dB across a noise range of 55–75 dB; g We were not able to draw any conclusions whether possible residual confounders or biases would reduce our effect estimate; h The overall judgement of the quality of the evidence was “very low”(0). Downgrading of the overall level of evidence, because only one study was available, made no sense.